Orbits HW – Space – Flashcards

the distance from one of these to a point on an ellipse to the other one of these always stays the same no matter where on the ellipse you are; also the Sun is at one of these for every planet orbit

widest "diameter" of ellipse

"size" of orbit, the average distance between Sun and planet

place in orbit where planet is closest to Sun

place in orbit where planet is farthest from Sun

Number describing the shape of an ellipse, how "squashed" it is

when a planet spins on its axis, giving it a day/night cycle

when a planet goes around the Sun, which determines its length of year

the force that "ties" a planet to the Sun (or a Moon to a planet)

plane of the solar system in which the planets orbit (and the name for this plane as it is seen on the sky from the surface of the Earth)

According to Kepler's laws as a planet orbits, it moves

Indicate which of these I would have to change in order to alter how long it takes a planet to orbit our Sun. Select all that apply.

One Astronomical Unit (AU) is equal to the semi-major axis of which object's orbit?

The image below shows three planet orbits around the same star. A: yellow circle semi-major axis 3.6AU B: white circle semi-major axis 2.3AU C: blue ellipse semi-major axis 2.3AU Which lists them by amount of time it takes to complete one orbit from longest to shortest?

Five planets orbit identical stars. The planet names, mass, and semi-major axis are as follows: Abydos: 0.5 Earth-mass planet with semi-major axis 20 AU Pern: 1 Earth-mass planet with semi-major axis 1 AU Arrakis: 45 Earth-mass planet with semi-major axis 0.3 AU Magrathea: 10 Earth-mass planet with semi-major axis 1 AU Trantor: 1 Earth-mass planet with semi-major axis 11 AU Using Kepler's third law, decide which answer lists the planets based on their orbital periods from longest to shortest.

Two students are discussing planet orbits. Student 1: The time it takes for a planet to orbit the Sun once is only determined by the semi-major axis of the orbit, not the eccentricity. Student 2: Eccentricity changes the shape of the orbit so the planet is sometimes closer to the Sun and moving faster, so I think eccentricity should affect the orbit period, too. Which student is correct?

Consider the two mythical planets orbiting the Sun, Derse and Prospit. Derse is in a circular orbit with a semi-major axis of 4 AU and takes 8 years to orbit once. Prospit is in a highly eccentric orbit with a semi-major axis of 4 AU. How long does it take the Prospit to complete one orbit?

If two planets have the same semi-major axis around the same star but they have different eccentricities, then

If two planets have the same semi-major axis around the same star but they have different eccentricities, then

Which of these observations allow me to measure the mass of a planet like Jupiter?

There is a gigantic black hole at the heart of our Milky Way galaxy. By their nature black holes are very difficult to detect, especially when they are not active. Astronomers have observed stars orbiting the black hole, as shown by this animation and this graph of star positions over 13 years. What information about a star's orbit would we need to know to calculate the mass of this black hole? Select all that apply.

Your friend Caz shows you a picture of himself on a scale on Earth, where the scale reads 144 pounds, and then shows you a picture of himself on the Moon, where the scale reads 24 pounds. Caz looks the same in both photos, so which describes what has happened?

Three students are about to watch the Apollo hammer-feather drop on the Moon and are discussing what will happen. Student 1: Neither object should fall because the Moon has no air, so there won't be any gravity. The astronauts fall to the surface because they have special suits that have more mass. Student 2: They should fall at the same time, since their masses are both very small compared to the mass of the Moon and there is no air to slow down the feather. Student 3: I think both will fall on the Moon but the feather should fall slower than the hammer, since it has less mass and greater air resistance. Which student is correct?

Astronauts float in the International Space Station. We say they are weightless, so are they experiencing a force of gravity?

Which of the following would make you weigh less than you do right now?

Two students are discussing force, mass, and the Earth and Sun. Student 1: I don't think the force is equal between the Earth and the Sun. The Earth goes around the Sun, so the force of the Sun on the Earth has got to be stronger than the Earth on the Sun. Student 2: The forces between the Sun and Earth are the same. Since the Earth has less mass and is easier to push, it is the one that orbits. Which student is correct?

While a star has vastly more mass than a planet, planets can have a slight effect on their star's motion. If a planet is close enough to its host star and has enough mass, it can shift the center of mass enough to make the star move noticeably over one orbit as shown in this animation. However, planets are dim compared to stars, so from realistic distances we only observe the star moving and never actually see the planet. Consider a Sun-like star with a planet in an orbit with a semi-major axis of 1 AU. In which case would the center of mass be farthest from the star, making it move more over one orbit?